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ASN Wikibase Occurrence # 227647
Last updated: 10 February 2020
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Time:c. 16:00
Type:Silhouette image of generic ask1 model; specific model in this crash may look slightly different
Schleicher ASK 21
Owner/operator:The Cu Nim Gliding Club
Registration: C-FLTY
C/n / msn: 21852
Fatalities:Fatalities: 2 / Occupants: 2
Other fatalities:0
Aircraft damage: Written off (damaged beyond repair)
Location:Black Diamond/Cu Nim Airport (CEH2), Black Diamond, AB -   Canada
Phase: En route
Departure airport:Black Diamond/Cu Nim Airport, AB (CEH2)
Destination airport:Black Diamond/Cu Nim Airport, AB (CEH2)
Investigating agency: TSB Canada
The Cu Nim Gliding Club Cessna 182N tow plane aircraft (C-FPZE) was conducting aerotow operations at Black Diamond/Cu Nim Aerodrome (CEH2), Alberta. The Cu Nim Gliding Club Schleicher ASK 21 glider (C-FLTY) was being used for instructional flights with an instructor and student on board.
The tow plane pilot involved in the occurrence had completed 2 aerotow operations before the occurrence flight, the first of which had departed at 1510.Footnote1
The occurrence glider flight was the 2nd flight of the day for the student and flight instructor involved in the occurrence. The 1st instructional flight had been completed at approximately 1030.
At 1549, the tow plane departed Runway 07 with the glider in tow and turned to the south while climbing to the intended release altitude of 5700 feet above sea level (ASL) (2000 feet above ground).
Around the time the aircraft crossed the extended centreline of Runway 07, the glider flight crew radioed the tow plane pilot and requested that he carry out some medium bank turns as part of the glider towing exercise. This was not briefed prior to departure. At this point, the tow plane was at approximately 5900 feet ASL. The tow plane completed a medium (approximately 30° bank) left turn of about 145°, which brought both aircraft over approximately midfield of CEH2, followed by a medium (approximately 30° bank) right turn of about 90°, which brought the aircraft to a track of 305° true (T) near the western edge of CEH2, at approximately 6100 feet ASL. The glider released from the towline halfway through this turn.
Typically, a glider pilot will release from the towline when the 2 aircraft are in straight and level flight. When the tow plane reached the anticipated release point, the glider had already released; however, the tow plane pilot was not aware. Shortly after, the glider flight crew called the tow plane pilot on the radio to thank him for the tow. The tow plane pilot could not see the glider but executed a left clearing turn of approximately 80°, as is standard procedureFootnote2 upon glider release. He did not initiate a descent at this point, but did begin preparing the aircraft for the approach and landing at CEH2.
Because the pilot of the tow plane could not see the glider, he entered a slight right turnin an effort to find the glider. This brought the tow plane to a track of 270°T. Still unable to see the glider, the tow plane pilot then proceeded to complete a 90° left turn, heading almost directly south. There was no attempt to communicate with the glider to determine its position.
When the glider released from the tow plane, halfway through the second medium turn at an altitude of approximately 6100 feet ASL, the glider flight crew proceeded to fly more or less on a track of 270°T. By releasing in a right turn, the glider was not in a position where the tow pilot would normally expect to see it, i.e., behind and to the right of the tow plane.
At 1555, when the aircraft were 0.5 nautical miles (NM) southwest of the threshold of Runway 07 and at an altitude of approximately 6075 feet ASL, the tow plane’s propeller struck the glider’s empennage. The time between the glider release and the collision was 34 seconds.
When the tow plane struck the glider, the vertical and horizontal stabilizers separated from the glider. The glider entered a dive from which it was unable to recover and struck terrain in a near-vertical attitude. The student pilot and instructor were fatally injured. Both were wearing parachutes at the time of the occurrence.
The tow plane sustained substantial damage to the propeller and cowling, and minor damage to the right wing. The pilot was not injured and managed to perform a successful forced landing at idle power on Runway 14 at 1557.

_________________________ (photo)

Accident investigation:
Investigating agency: TSB Canada
Status: Investigation completed
Duration: 6 months
Download report: Final report


Overview of the tow plane and glider’s flight paths, (TSB)

Revision history:

27-Jul-2019 01:00 Geno Added
27-Jul-2019 01:46 RobertMB Updated [Damage, Narrative]
27-Jul-2019 11:30 streetf117 Updated [Aircraft type, Registration, Cn, Source]
27-Jul-2019 12:39 RobertMB Updated [Aircraft type, Registration, Operator, Source]
27-Jul-2019 12:45 Iceman 29 Updated [Nature, Source, Embed code]
27-Jul-2019 16:01 Aerossurance Updated [Embed code, Narrative]
28-Jul-2019 16:13 I42 Updated [Embed code]
07-Aug-2019 09:29 harro Updated [Narrative]
10-Feb-2020 18:12 harro Updated [Phase, Nature, Narrative, Photo, Accident report, ]

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